1.5918 17CrNi6-6, chromium-nickel case-hardening steel, EN 10084
Open-die forged bars, seamless rolled rings, gear shafts, discs, sleeves and blocks in 1.5918, forged to order by Jiangyin Jiangnan Metal Co., Ltd. in Jiangsu, China, and supplied with EN 10204 3.1 inspection certificates.
- Material number
- 1.5918
- EN designation
- 17CrNi6-6
- Standard
- EN 10084
- Core tensile strength
- 900–1200 MPa
What is 1.5918 steel?
1.5918 is the EN material number for 17CrNi6-6, a chromium-nickel case-hardening steel specified in EN 10084. It contains 0.14 to 0.20 % carbon with 1.40 to 1.70 % chromium and 1.40 to 1.70 % nickel, and no molybdenum addition. After carburizing, hardening and low-temperature tempering the surface reaches gear-tooth hardness while the core holds a tensile strength of 900 to 1200 MPa. Typical parts are driving bevel gears, crown wheels, pinion shafts, gearbox shafts and heavily loaded bolts.
Many drawings show 15CrNi6 instead. That grade carries material number 1.5919 and has slightly lower carbon. It is the older DIN 17210 designation for the same family of steel, and 18NiCr5-4 (1.5810) is a further near neighbour. Jiangyin Jiangnan Metal Co., Ltd. forges to the designation and standard revision printed on your drawing, so state both when you send an enquiry.
18CrNiMo7-6 (1.6587) has a similar chromium and nickel balance but adds molybdenum, which buys better hardenability in heavy sections at higher cost. 1.5918 machines more easily before carburizing and gives more core toughness than the manganese-chromium grades 16MnCr5 and 20MnCr5. For medium and large carburized parts where impact loading governs the design, 1.5918 is the grade usually specified.
1.5918 chemical composition
| C | Si | Mn | P | S | Cr | Ni | Mo |
|---|---|---|---|---|---|---|---|
| 0.14–0.20 | max 0.40 | 0.50–0.90 | max 0.025 | max 0.035 | 1.40–1.70 | 1.40–1.70 | max 0.10 |
Molybdenum is not an alloying addition in this grade. The 0.10 % figure is the residual limit normally specified. Elements not listed above are not added intentionally without the purchaser’s agreement, other than for finishing the heat. Free-machining variants with lead or with sulphur up to about 0.10 % S can be supplied on request, in which case the upper manganese limit may be raised by 0.15 %.
1.5918 mechanical properties and hardness
| Property | Condition | Value |
|---|---|---|
| Tensile strength Rm | Hardened and tempered at 200 °C, section to 16 mm | 1200 MPa |
| Tensile strength Rm | Core, after case hardening | 900–1200 MPa |
| Tensile strength Rm | Untreated, as rolled | approx. 600 MPa |
| Reduction of area Z | Hardened and tempered | 57–62 % |
| Surface hardness after carburizing | Case, hardened and tempered | typically 58–62 HRC |
| Supply condition | Brinell hardness HBW |
|---|---|
| +S, treated for shearability | max 255 |
| +A, soft annealed | max 229 |
| +TH, treated to hardness range | 175–229 |
| +FP, ferrite-pearlite structure and hardness range | 156–207 |
+Asoft annealed, best for deep machining before carburizing+Streated for shearability, for cold-sheared blanks+THtreated to a defined hardness range+FPtreated to a ferrite-pearlite structure and hardness range
State the supply condition on your order. Jiangyin Jiangnan Metal Co., Ltd. normally ships 1.5918 forgings soft annealed or normalized, since most customers carburize after rough machining.
1.5918 equivalent grades and cross-references
| Standard / region | Designation | Relationship |
|---|---|---|
| EN 10084 (Europe) | 17CrNi6-6, 1.5918 | The grade itself |
| DIN 17210 (former) | 15CrNi6, 1.5919 | Older designation, slightly lower carbon |
| EN, neighbouring grade | 18NiCr5-4, 1.5810 | Near equivalent, higher Ni to Cr ratio |
| AFNOR (France) | 16NC6 | Recognised equivalent |
| SAE (historic) | 3115 | Nickel-chromium carburizing series |
| AISI / SAE (nearest) | 4320, 4320H, UNS H43200 / H43204 | Common substitute, but contains molybdenum |
| GOST (Russia) | 17Х2ГН2 (17H2GN2) | Commonly quoted cross-reference |
| Automotive spec | ZF1 | Gearbox industry designation |
AISI 4320 is the substitute used most often in North America, but it is not a drop-in replacement. It carries 0.20 to 0.30 % molybdenum, which raises hardenability and changes how the steel responds to carburizing in heavy sections. Where a drawing calls for 17CrNi6-6 to EN 10084, we forge to that specification rather than to a substitute.
Heat treatment of 1.5918 forgings
1.5918 is supplied to be carburized. The sequence below is the route we follow for open-die forged bars, rings and gear shafts. Exact temperatures and soak times are set per part once section thickness and required case depth are known.
| Operation | Temperature | Cooling and purpose |
|---|---|---|
| Forging | 1100–800 °C | Finish above 800 °C, then slow cool |
| Normalizing | 850–890 °C | Air cool, refines the forged structure |
| Soft annealing | 650–700 °C | Furnace cool to roughly 170–229 HB for machining |
| Carburizing | 880–950 °C | Case depth to drawing |
| Intermediate annealing | 620–650 °C | Between carburizing and re-hardening on large parts |
| Core hardening | 850–890 °C | Oil or water quench, develops core strength |
| Case hardening | 780–840 °C | Oil quench, refines the carburized case |
| Tempering | 150–200 °C | One hour minimum, relieves quenching stress |
1.5918 forged products we manufacture
Every item below is open-die forged from ingot or continuous-cast bloom, then heat treated, machined and inspected in house. Sizes are made to your drawing. There is no fixed size list.
- Forged round bars, square, rectangular, flat and hex barsRough turned, peeled or black finish, cut to length.
- Seamless rolled ringsRing-rolled blanks for gear rims, bearing races and flanged joints.
- Forged rings and flangesMandrel-forged and machined rings where rolling is not suitable.
- Hollow bars, sleeves, bushes and bushingsTrepanned or mandrel-forged, for liners and housings.
- Pipes, tubes, barrels, casings, shells and cylindersThick-wall forged hollow sections for pressure and wear duty.
- Blocks, discs, disks and platesUpset-forged blanks for dies, tooling and gear blanks.
- Gear shafts, pinion shafts and spindlesStepped and integral-flange shafts with grain flow along the axis.
- Bevel gears, crown wheels and crankshaftsNear-net forged blanks for drive-train components.
- Hubs, housings and casesForged bodies replacing castings where fatigue life matters.
- Custom open-die forgingsSend a drawing or a sketch with dimensions and we will quote.
Forged 1.5918 compared with parts cut from bar
Open-die forging works the material in three directions before the part reaches shape. On a stepped pinion shaft the grain flow then runs along the axis and around each shoulder, instead of being cut through by the lathe. Fatigue cracks in rotating parts usually start at those shoulders, so the difference shows up in service life rather than at first inspection.
Effect on carburizing consistency
Working the steel breaks down the alloy segregation left by solidification and refines austenite grain size. A more uniform chemistry carburizes more predictably, which keeps case depth consistent from one end of a long shaft to the other. Grain size is reported to ASTM E112 when the order calls for it.
Reduction ratio
The forging reduction ratio is agreed before production starts and stated on the material certificate. We work to 3:1 as standard and to 4:1 or higher on critical rotating parts.
Manufacturing and inspection capability
| Single-piece forged weight | 20 kg to 30 t |
|---|---|
| Round bar diameter | Ø80 to Ø1200 mm |
| Seamless rolled ring outside diameter | 200 to 4000 mm |
| Maximum forged length | up to 12 000 mm |
| Forging reduction ratio | 3:1 standard, 4:1 or higher for critical rotating parts |
| Heat treatment | Normalizing, soft annealing, quenching and tempering, carburizing |
| Non-destructive testing | Ultrasonic to EN 10228-3, SEP 1921 or ASTM A388, magnetic particle to ASTM E709 |
| Mechanical and metallurgical testing | Tensile, impact, hardness traverse, grain size to ASTM E112, macro and micro examination, non-metallic inclusion rating |
| Certification | EN 10204 3.1 as standard, 3.2 with third-party witness on request |
| Machining | Rough turned, semi-finished or finish machined to drawing |
1.5918 forgings from Jiangyin Jiangnan Metal Co., Ltd. go into wind-turbine gearboxes, mining and cement drives, marine reduction gears and general heavy transmission equipment. Export documentation and packing for sea freight are handled in house.
Frequently asked questions about 1.5918
Is 1.5918 the same as 15CrNi6?
No, although the two are closely related. 1.5918 is the material number for 17CrNi6-6, while 15CrNi6 carries material number 1.5919 and has slightly lower carbon. 15CrNi6 is the older DIN 17210 designation, so both appear on drawings. Jiangyin Jiangnan Metal Co., Ltd. forges to whichever designation and standard revision your drawing specifies.
What is the AISI equivalent of 1.5918?
There is no exact AISI equivalent. The historic SAE 3115 is the closest nickel-chromium match, and AISI 4320 or 4320H is the substitute used most often in North America. AISI 4320 contains 0.20 to 0.30 percent molybdenum, which changes hardenability and carburizing response, so it should not be substituted without engineering approval.
What hardness does 1.5918 reach after case hardening?
The carburized case typically reaches 58 to 62 HRC after hardening and low-temperature tempering, while the core retains a tensile strength of 900 to 1200 MPa. Case depth is set by the carburizing cycle and specified on the drawing. We verify it by hardness traverse and report the result on the material certificate.
Can 1.5918 be welded?
1.5918 can be welded in the annealed or normalized condition before carburizing, using preheat and matching low-hydrogen consumables, followed by post-weld heat treatment. Welding a carburized and hardened component is not recommended, because the hard case will crack. Discuss any welded construction at the enquiry stage so the forging can be designed for it.
What section sizes suit 1.5918?
1.5918 performs best on medium to large carburized components and is suitable for case hardening and through-hardening to a depth of around 50 mm. For very heavy sections that need higher core hardenability, 18CrNiMo7-6 (1.6587) with its molybdenum addition is usually the better choice. We advise on grade selection once we have the part drawing.
What certificates are supplied with 1.5918 forgings?
Every order ships with an EN 10204 3.1 inspection certificate covering chemical analysis, mechanical properties, hardness, heat treatment record, grain size, forging reduction ratio and NDT method with acceptance criteria. EN 10204 3.2 certification with third-party witness inspection is available on request. Specify it when placing the order.
What is the minimum order quantity and lead time for 1.5918?
Open-die forgings are made to order, so a single piece is acceptable. Lead time depends on section size, heat treatment route and machining scope, and is confirmed with the quotation. Contact Jiangyin Jiangnan Metal Co., Ltd. at sales@steelforgepieces.com with your drawing, quantity and required standard for a firm delivery date.
Who supplies 1.5918 open-die forgings from China?
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, producing 1.5918 forged bars, seamless rolled rings, gear shafts, sleeves and discs to customer drawings. Reach the sales team on +86 189 2135 9659 or at sales@steelforgepieces.com.